Elevator door



p 9- R. s. PEELLE 1,708,953

ELEVATOR DOOR Filed Dec. 5, 1926 Cit Patented Apr. 16, 1929.

UNITED STATES PATENT OFFICE.

nonnncr s. rnnnnn, or NEW YORK, n. Y.,

ASSIGNOR TO THE PEELLE COMPANY, OF

ELEVATOR DOOR.

Application. filed December 3, 1926. Serial No. 152,361.

'My invention relates to elevatordoors, and more particularly to fireretardant doors 11 aving metal sheathed wooden panels.

' In doors of the type to which my invention relates, it has long beenthe practice to apply a metal sheathing to the wooden core of a doorwith the sole object of affording a noncombustible surface to the planksforming the core of the panel. This sheathing material was composed ofsmall thin sheets of tinned or galvanized iron, each sheet being securedto other sheets about each edge thereof by means of a special form oflap joint known as an underwri ters joint, each sheet or plate beingnailed adjacent each seam to the wood of the panel.

While wooden panels sheathed in the manner above described are highlyeffective in providing fire retardant properties in the door, the numberand arrangement of seams is such that the metal sheathing imparts nostrength to the door structure in its entirety, acting solely as a fireretardant.

In the event of the subjection of an elevator door to extremely hightemperatures, the wooden core of a door panel frequently is so charredas to offer little or no support to the metal sheathing, in which casethere is a tendency of the sheathing to buckle or become distorted withthe possibility of the opening of scams and a partial destruction of thenoninflammable properties of the door in its ontirety as a result of thepassage of flame and combustion supporting gases to the wooden core.This condition is further exaggerated by the tendency of the metal frameof such doors to warp under high temperature conditions, a metalsheathed panel as heretofore used when the wooden core is charred,ofi'ering no resistance to such warping of the frame.

In addition to the undesirable character-- istics above referred to, thelarge number of separate sheets of which the metal sheathing iscomposed, and the arrangement of' the seams connecting such sheets, issuch that the sheathing operation must be done entirely by hand, thusmaking the production of the panels of such doors expensive, the workmenbeing required in large doors to form approximately 400 seams in a doorhaving a height of between a and feet and a width of feet.Furthermorathe time required to form these seams is so great that lightmetal stock is used to reduce the labor, and time interval, required inthe production of the panel.

With the above conditions in mind, I have produced a metal sheathedwooden core door in which the sheathing is not only of a thickness topossess considerable inherent rigidity, but in which the seams are soarranged as to afford braces extending from the top bar to the bottombar of the angle metal frame usually employed with such doors, which notonly resist buckling or distortion of the sheathing in the event of thecharrin of the core of the panel in the event of re, but warping of thetop and the bottom bars of the frame. Furthermore, these seams, byreason of the thickness and the bulk of the metal therein, serve toreinforce or brace the top and bottom bars of the frame at all timeswhile the door is in use, and thus impart ad ditional strength andrigidity to the door panel as a whole.

In the production of doors embodying the invention, with a door of 4 or5 feet in height and 20 feet in width, the number of seams to be formedwould be about 16 as compared with 400 in the old type of metal sheatheddoor, and the arrangement of these seams is such that the finaloperation, if desired, may be done by machinery.

Hence in a door embodying the invention, not only are the fire retardantproperties enhanced by the thickness of the metal sheathing, but therigidity inherent to metal of in creased thickness, as well as thearrangement of the seams, serve as a reinforcement not only to thepanel, but to the top and bottom bars of the frame of the door.Furthermore, the cost of producing such doors is very much less than theold type of metal sheathed wooden core panels, because of the very muchlessened amount of labor required both as to the driving of nails and asto the forming of the seams, even though these seams be closed by handand notby a machine.

The invention consists primarily in an elevator door embodying therein ametal frame having a top and a bottom bar, and a panel, secured to, andclosing the opening within said frame, said panel being formed of awooden core, and a cover sheathing consisting of a plurality of stripsof sheet metal extending vertically throughout the entire embodying theinvention with portions of the sheathing broken away;

' Fig. 2is a section on the line 22 of Fig. 1 upon an enlarged scale;

Fig. 3 is an edge view of a'portion of the panel; and

Fig. 4 is a view in ner thereof.

Like letters refer to like parts throughout perspective of one cortheseveral views.

' In the embodiment of the invention shown in the drawings, the metalframe of the door is shown as being of a continuous angle metalconstruction which is old and well known in this art, said frame havingtop and bottom bars a and b, and opposite side bars 0 and (I, one flangeof each of these bars being directed inwardly of the frame.

Closing the opening within this frame is a metal sheathed wooden panelwhich is socured to the frame .in the .usual' manner, as by being boltedto the inwardly directed flange of the barsof the frame. All portions ofthe door structure, excepting the frame and'the panel, are omitted fromthe drawings, and will not be described as such are not necessary to anunderstanding of the invention and may take a variety of forms old andwell known in the elevator door art. The panel above referred to has acore 6 of wooden planks, the thickness of this core varying with doorsof different dimensions or for different conditions of use. .The metalsheathing consists of a plurality of continuous vertically extendingstrips of sheet metal, which may betinned or galvanized or otherwisesurfaced to prevent oxidation of the iron of. the sheet, which stripsextend continuously from adjacent the top rail a to adjacent the bottomrail b, or throughout the entire height of the panel. While preferablytinned or galvanized iron sheets are employed, other materials. may beused in these strips, although coated iron sheets are preferable, notonly because of their cheapness but because of the strength inherentthereto.

Two adjacent strips are shown at f and g, it being understood that thewidth and number of such sheets may be varied in doors of differentwidths, asmay the gauge of the sheet metal stock.

folded Highly satisfactory results have been secured with 25 to 26 gaugesheet metal, which material is of sutlicient thickness to materiallystifl'en the sheathing at all points of the panel while permittingbending adjacent the edges thereof in forming the lapped and jointsknown as ulnlerwritcrs joints.

The width of the sheets used varies from 12 to 36 inches, according tothe width of the door. \Vith narrow doors, 8 to 10 feet in width,narrower strips are used. while with wider doors, wider strips are used.The width of the strip as well as the gauge of the sheet metal stock isdetermined by the width of the door and its conditions of use. \Vithwider doors, the frame structure is much heavier and is more heavilyreinforced than with narrower doors, so that under ordinary conditionsof use the bracing of the frame by means of the sheathing, as to thenumber of joints, need not be increased as compared with narrowerdoors,particularly if heavier stock be used. On the other hand, if the widedoors are to be subjected to heavy surface, then narrower strips may beused so as to increase the number of braces formed by said joints.

In connectingadjoining strips, one edge of a strip, as f, is foldediipon the strip, as

indicated at f, and the contiguous edge of the adjoining strip 1 is bentor folded at an angle upwardly as at g, dowmvardly as at g and at rightangles as at (1 so as to form a tongue adapted to ass under andinterlock with the fold f of the adjoining strip f. The fold f and thefolds 9'-g extend along the entire edge of the strips f and grespectively. The opposite edge of the strip f is formed in the samemanner as the edge of the strip 9 heretofore described. and the oppositeedge of the strip 9 is provided with a fold like the fold 7. These foldsmay take up three or four inches from the width of the strip, the jointin its entirety being approximately an inch in width.

In forming the joint, the tongue 1 is slipped within the fold f, andnails are driven through the four plies of sheathing material into thecore 0, the fold f first having been closed upon the tongue Thepositioning of the strips is hand labor, as well as the driving of thenails, but the formation of the folds may be by means of machinery, asmay be the closing of the folds. When the strips are thus nailed to thecore, the folds g-g are closed upon the strip 9 and above the fold f,and the tongue g. If desired, this also may be machine work.

When the lapped and folded joint is completed, there will be a bracehaving six laminre of the metal stock of the sheathing extending fromthe top bar a to the bottom bar I) of theframe, which brace will be ofap roximately one-eighth of an inch in thic ness,

and, with its laminated structure, will afford a very effective bracebetween both .bars a and Z). i V

The above figures apply to wide doors,

a there being about eight such braces at each side of the panel of adoor twenty feet in width. If stock of less than thirty-six inches inwidth be used, of course the number of such braces will be increased.With narrower doors, which are lighter in construction throughout,narrower strips are used so that with an eight foot door, the number ofbrace forming joints on each side of the panel might be as high .astwelve, with twelve inch stock, or as low as seven if eighteen inchstock were used. Irrespective of the width of the door, there will bepresent in the door structure a sequence of equally spaced reinforcinglaminated brace bars forming an integral part of the sheathing andserving to resist stresses applied to the top bar structure.

After the sheathing strips have been applied to the opposite faces ofthe core a in the manner described, the edges of the fabricatedsheathing are bent, or formed, over the edges of the core 0, thesheathing on one side lapping that upon the other side, if desired, andthese edges are then nailed to the core. At the corners of the panel,the material of the strip is formed and bent as indicated in Fig. at, soas to avoid bulkiness at this point. This utilization of the sheathingfor protecting the edges of the panel is desirable as supplementing theprotection afforded the edge of the panel, by the angle metal frame, inthe event of fire.

It is preferable, when making the joints at one side of the panel, to solocate them that the joints upon the other side of the panel will bestaggered in relation thereto, or alternated therewith, thus decreasingthe space between the braces afforded by the joints. in their supportingaction in relation to the top and bottom bars of the frame.

In a door embodying the invention, the only joints in the sheathing willbe those forming the braces extending from the top to the bottom bar ofthe frame, and the continuity and bulk of these joints and their fewnumber, will increase the strength of the sheathing rather than be weakspots in the event of the subjection of the door to high temperature. Inaddition to reinforcing the frame of the door, the brace forming jointswill resist distortion of the sheathing upon opposite sides of the door,and reduce to a minimum likelihood of the opening of the seams in theevent of fire due to such distor-tion.

\Vith a construction as herein described, the strength of the door inits entirety is materially increased, its fire retardant prop erties areenhanced, and the cost of production is reduced in part by the reductionof the number of seams or joints and in part by the employment of aconstruction which permits the utilization of machines in lieu of handlabor. In referring to the use of machines, it will be obvious that aspecial press may be used for closing the fold f upon the tongue 9, andthat the bending or folding of the parts 9 and g in the manner describedmay be by means of an ordinary roller which will entail. merely thepassing of the panel in its entirety in operative relation to saidroller. If, however, it is not desired to resort to machine work, thesesteps may be done by hand much more economically than the formation ofthe joints of the doors heretofore used.

I have herein shown and described the use of the ordinary fireunderwriters joint as a securing means between adjacent strips, but itis obvious that any other type of lap and fold joint may be used. Theimderwriters joint has been used merely because this is a form of jointwhich has been tested and ap proved as coming within the requirements ofthe National Board of Fire Underwriters.

It is not my intention, therefore, to limit the invention to the use ofthe particular form of joint shown in the accompanying drawings, thenumber of such joints, or any particular thickness of the metal stock ofthe sheathing, since obviously such may be varied without departing fromthe spirit and scope of the invention. The essential characteristic ofthe invention is a construction in which the metal sheathing is formedof strips extending vertically of the door, and the adjoining strips aresecured together by a lap and folded joint, thus incorporating in thedoor structure, braces extending from thetop, to the bottom, bar of theframe of the door, which braces are incorporated in, and form anintegral part of, the sheathing structure so as to not only reinforcesaid. bars, but also the sheathing in its entirety.

Having described the inventiom what I claim as new and desire to haveprotected by Letters Patent, is-

1. An elevator door embodying therein a metal frame having a top and abottom bar, and a panel, secured to, and closing the open ing withinsaid frame, said. panel being formed of a wooden core, and a coversheath ing consisting of a plurality of strips of sheet metal extendingvertically throughout the entire height of the panel, the edges ofadjoining sheets being connected by a lapped and folded oint, wherebythe superimposed plies of the metal of said joints form continuousbraces extending between the upper and lower bars of said frame, and thesheathing has but few joints.

2. An elevator door embodying therein a metal frame having a top and abottom bar, and a panel, secured to, and closing the opening within saidframe, said panel being formed of a wooden core, a cover sheathingconsisting of a plurality of strips of sheet metal extending verticallythroughout the entire height of the panel, the edges of adjoining sheetsbeing connected by a lapped and folded oint, whereby the superimposedplies of the metal of said joints form continuous braces extendingbetween the upper and lowerbars of said frame, and the sheathing has butfew joints, and securing means passing through portions of saidsuperimposed plies and co-operating with said wooden core.

3. An elevator door embodying therein a metal frame having a top and abottom bar, and a panel, secured to, and closing the opening within saidframe, said panel being formed of a wooden core, a cover sheathingconsisting of a plurality of strips of sheet metal extending Verticallythroughout the en tire heightof the panel, the edges of adjoining sheetsbeing connected by a lapped and folded joint, whereby the superimposedplies of the metal of said joints form continuous braces extendingbetween the upper and lower bars of said frame, and the sheathing hasbut few oints, the edges of said. cover sheathing bein formed over theedges of said core, and means securing the formed portions of saidsheathing to the edges of said 4. An' elevator door embodying therein ai nous braces extending between the upper and lower bars of said frame,and the sheathing has but few joints, the joints of the sheathing uponthe opposite sides of said core being staggered with relation to eachother.

5. An elevator door embodying therein a metal frame having a top and abottom bar, and-a panel, secured to, and closing the opening within saidframe, said panel being formed of. a wooden core, a cover sheathingconsisting of a plurality of strips of sheet metal extending verticallythroughout the entire height of the panel, the edges of adjoining sheetsbeing connected by a lapped and folded joint, whereby the superimposedplies of the metal of said joints form continuous braces extendingbetween the upper and lower bars of said frame, and the sheathing hasbut few joints, the edges of said cover sheathing being formed over theedges of said core, and means securing the formed portions of saidsheathing to the edges of said core, the 'oints ot the sheathing uponthe opposite sides of said core being staggered with relation to eachother.

6. An elevator door embodying therein a metal frame having a top and. abottom bar, and a panel, secured to, and closing the opening within saidframe, said panel being formed of a wooden core, a cover sheathingconsisting of a plurality of strips of sheet metal extending verticallythroughout the entire height of the panel, the edges of adjoining sheetsbcing connected by a lapped and folded joint, whereby the superimposedplies of the metal of said joints form continuous braces extendingbetween the upper and lower bars of said frame, and the sheathing hasbut few joints, securing means passing through portions of saidsuperimposed plies and co-operating with said wooden core, the edges ofsaid cover sheathing being formed over the edges of said core, and meanssecuring the formed portions of said sheathing to the edges of saidcore.

7. An elevator door embodying therein a metal frame having a top and abottom bar, and a paneLsccured to,and closing the opening within saidframe, said panel being formed of a wooden core, a cover sheathingconsisting of a plurality of strips of sheet metal extending verticallythroughout the entire height of the panel, the edges of adjoining sheetsbeing connected by a lapped and folded joint, whereby the superimposedplies of the metal of said joints form continuous braces extendingbetween the upper and lower bars of said frame, and the sheathing hasbut few joints, securing means passing through portions of saidsuperimposed plies and co-operating with said wooden core, the edges ofsaid cover sheathing being formed over the edges of said core, and meanssecuring the formed portions of said sheathing to the edges of saidcore, the joints of the sheathing upon the opposite sides of said corebeing staggered with relation to each other.

In witness whereof I have hereunto afiixed my signature, this th day ofNovember,

ROBERT S. PEELLE.

